This invention relates generally to gas turbine engines, and more particularly, to methods and apparatus to facilitate stall avoidance of gas turbine engines using an aerodynamic stability management system.
Gas turbine engines have limited ranges of operation due to aerodynamic phenomena that occur in the compressor system such as rotating stall. Rotating stall manifests itself as a region of severely reduced flow that rotates at a fraction of the compressor rotational speed and causes a drop in performance. Gas turbine engines stall primarily due to sudden acceleration, pressure distortion and/or engine degradation. Sudden acceleration is caused by feeding an excessive amount of fuel to the gas turbine engine. Pressure distortion is caused when an operator takes corrective or evasive action and the gas turbine engine inlet experiences irregular air flow pressure. Currently, engine fuel scheduling is developed through many trials and error, including allowance for deterioration. Additionally, there is currently no means to intelligently govern engine maintenance and to sense for missing rotor blades.
Engine stall affects operational safety and damages engine equipment causing maintenance costs and engine degradation to increase. Consequently, there is a need for a system that can avoid gas turbine engine stall by monitoring operational parameters of the engine and adjusting available control devices in response to those operational parameters. Further, there is needed a system that uses these same operational parameters for reducing engine deterioration.